RESUMEN
Granger causality model is an analysis method that requires no priori knowledge and emphasizes time sequence. Such model applied to brain effective connectivity network can reflect the directional connectivity among brain regions or neurons. This paper reviews the principle of Granger causality model, basic test steps and improved models, analyzes and discusses applications and existing problems of Granger causality model in brain effective connectivity network.
Asunto(s)
Humanos , Encéfalo , Fisiología , Mapeo Encefálico , Simulación por Computador , Modelos Neurológicos , Neuronas , FisiologíaRESUMEN
Arterial spin labeling (ASL) technique is a kind of perfusion functional magnetic resonance imaging method that is based on endogenous contrast, and it can measure cerebral blood flow (CBF) noninvasively. The ASL technique has advantages of noninvasiveness, simplicity and relatively lower costs so that it is more suitable for longitudinal studies compared with previous perfusion methods, such as positron emission tomography (PET), single photon emission computed tomography (SPECT), CT and the contrast agent based magnetic resonance perfusion imaging. This paper mainly discusses the current clinical applications of ASL in brain diseases as cerebrovascular diseases, brain tumors, Alzheimer's disease and epilepsy, etc.
Asunto(s)
Animales , Humanos , Encefalopatías , Diagnóstico , Neoplasias Encefálicas , Diagnóstico , Circulación Cerebrovascular , Trastornos Cerebrovasculares , Diagnóstico , Imagen por Resonancia Magnética , Métodos , Perfusión , Marcadores de SpinRESUMEN
Objective To investigate the association between chlamydia pneumoniae(Cpn)and atherosclerosis obliterans(ASO). Methods Sixty ASO patients and 40 healthy persons were selected,and their Cpn DNA expressions in venous blood determined by polymerase chain reaction(PCR). Results The ASO patients had significantly higher positive expression rate of Cpn DNA than that of healthy persons(78. 33% vs. 47.50% ,P ＜0.05). In all 60 cases the Cpn DNA expressions were positively correlated with the severity of ASO. Conclusions Cpn DNA expression closely relates with ASO severity,and it plays an important role in the ASO pathogenesis.